<template>
  <view>
    <!-- 自定义的搜索组件 -->
    <my-search @click="gotoSearch"></my-search>
   <view class="scroll-view-container">
     <!-- 左侧滑动区-->
     <scroll-view class="left-scroll-view" scroll-y="true" :style="{height: wh + 'px'}">
       <block v-for="(item,i) in cateList" :key="i">
       <view class="left-scroll-view-item" @click="activeChanged(i)" 
       :class="{active: active===i}">
       {{item.cat_name}}
       </view>
      </block>
     </scroll-view>
     <!-- 右侧滑动区-->
     <scroll-view scroll-y="true" :style="{height: wh + 'px'}" :scroll-top="scrollTop">
      <view class="cate-lv2" v-for="(item2,i2) in cateLevel2" :key="i2">
        <!-- 二级分类标题 -->
        <view class="cate-lv2-title">
          / {{item2.cat_name}} /
        </view>
        <!-- 三级分类列表 -->
        <view class="cate-lv3-list">
          <view class="cate-lv3-item" @click="gotoGoodsList(item3)"
           v-for="(item3,i3) in item2.children" :key="i3">
            <image :src="item3.cat_icon"></image>
            <text>{{item3.cat_name}}</text>
          </view>
        </view>
      </view>
     </scroll-view>
   </view>
  </view>
</template>

<script>
  // 导入自己封装的 mixin 模块
  import badgeMix from '@/mixins/tabbar-badge.js'
  export default {
    data() {
      return {
        // 当前设备可用的高度
        wh:0,
        // 分类数据的列表
        cateList:[],
        active:0,
        // 二级分类列表
        cateLevel2:[],
        scrollTop:0
      };
    },
    mixins:[badgeMix],
    onLoad(){
      // 获取设备可用的高度
      const sysInfo = uni.getSystemInfoSync()
      // 实际可用高度 = 屏幕高度 - navigationBar高度 - tabBar高度 - 自定义的search组件高度
      this.wh = sysInfo.windowHeight - 50
      this.getCateList()
    },
    methods:{
     async getCateList(){
      const {data:res} = await  uni.$http.get('/api/public/v1/categories')
      if(res.meta.status!== 200) return uni.$showMsg()
      this.cateList = res.message
      this.cateLevel2 = res.message[0].children
      },
      activeChanged(i){
        this.active = i
        // 更新二级分类列表
        this.cateLevel2 = this.cateList[i].children
        this.scrollTop = this.scrollTop === 0?1:0
      },
      // 跳转到商品列表页面
      gotoGoodsList(item){
        uni.navigateTo({
          url:'/subpkg/goods_list/goods_list?cid='+item.cat_id
        })
      },
      gotoSearch(){
       uni.navigateTo({
         url:'/subpkg/search/search'
       })
      }
    }
  }
</script>

<style lang="scss">
.scroll-view-container{
  display: flex;
  .left-scroll-view{
    width: 120px;
    .left-scroll-view-item{
      background-color: #F7F7F7;
      line-height: 60px;
      text-align: center;
      font-size: 12px;
      &.active{
        background-color: #FFFFFF;
        position: relative;
        &::before{
          content: '';
          display: block;
          width: 3px;
          height: 30px;
          background-color: #C00000;
          position: absolute;
          top: 50%;
          left: 0;
          transform: translateY(-50%);
        }
      }
    }
  }
}
.cate-lv2-title{
  font-size: 12px;
  font-weight: bold;
  text-align: center;
  padding: 15px 0;
}
.cate-lv3-list{
  display: flex;
  flex-wrap: wrap;
  .cate-lv3-item{
    width: 33.33%;
    display: flex;
    flex-direction: column;
    justify-content: center;
    align-items: center;
    margin-bottom: 10px;
    image{
      width: 60px;
      height: 60px;
    }
    text{
      font-size: 12px;
    }
  }
}
</style>
